Chronic diseases and impaired function related to physical inactivity are major factors in the disability, diminished quality of life, and burgeoning health care costs facing older women. Although the growing number of older women serving as family caregivers could especially benefit from the physical and psychological effects of regular, moderate- intensity endurance exercise, their life circumstances typically make it difficult to attend classes regularly away from home. While supervised home-based physical activity has proven to be effective in producing long- term physical and mental health benefits in community samples of older adults, a critical next step is to determine its effectiveness in such at- risk subgroups for whom it is particularly indicated. The objectives of this study are to: (1) determine the initial (6 months) and longer-term (12 months) effectiveness of a home-based moderate- intensity physical activity program in promoting significant increases in physical performance and functioning in older women caregivers; (2) evaluate the efficacy of the physical activity regimen for promoting initial and longer-term changes in a broad array of day-to-day functioning and well-being (quality of life) variables; (3) use the study as an opportunity to evaluate the effects of family caregiving on ambulatory blood pressure and heart rate responses as indicators of stress in the natural setting, as well as an opportunity to enhance knowledge with respect to the measurement of physical activity among older women. The study design is a one-year randomized trial in which women ages 50-75 years serving as primary caregivers for a relative with dementia will be randomly assigned to one of three conditions: supervised home-based physical activity training; music/relaxation training; or general support/instruction. All programs are designed to enhance long-term participation. Data will be collected at baseline and at 6 and 12 months using age-relevant physical performance tests, a comprehensive set of rated functioning and well-being scales, and several promising measures of physical activity. Our primary research hypotheses are that subjects assigned to physical activity training will demonstrate significant increases in physical functioning and performance, maintained through 12 months, relative to the non-exercise control conditions. Additional major questions of interest focus on the comparative changes in rated functioning and psychological well-being for the three conditions across the 12-month period; whether preliminary data suggesting significant negative effects of family caregiving on blood pressure responses in the natural setting are verified in a larger, more representative sample of caregivers; and the extent to which blood pressure and heart rate responses in the natural setting are influenced, both acutely and over time, by the different intervention regimens. This study will contribute important information with respect to the development of effective, potentially low-cost strategies for preventing caregiver disability and maintaining caregiver health, functioning, and well-being.